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Single Idea 10075

[filed under theme 5. Theory of Logic / E. Structures of Logic / 5. Functions in Logic ]

Full Idea

A 'partial function' is one which maps only some elements of a domain to elements in another set. For example, the reciprocal function 1/x is not defined for x=0.

Gist of Idea

A 'partial function' maps only some elements to another set

Source

Peter Smith (Intro to Gödel's Theorems [2007], 02.1 n1)

Book Ref

Smith,Peter: 'An Introduction to Gödel's Theorems' [CUP 2007], p.8

Related Idea

Idea 13811 A 'total' function ranges over the whole domain, a 'partial' function over appropriate inputs [Bostock]


The 13 ideas with the same theme [elements in logical systems to create new objects]:

First-level functions have objects as arguments; second-level functions take functions as arguments [Frege]
'Propositional functions' are ambiguous until the variable is given a value [Russell]
We can identify functions with certain sets - or identify sets with certain functions [Putnam]
A 'zero-place' function just has a single value, so it is a name [Bostock]
A 'total' function ranges over the whole domain, a 'partial' function over appropriate inputs [Bostock]
A 'total function' maps every element to one element in another set [Smith,P]
The 'range' of a function is the set of elements in the output set created by the function [Smith,P]
A 'partial function' maps only some elements to another set [Smith,P]
Two functions are the same if they have the same extension [Smith,P]
An argument is a 'fixed point' for a function if it is mapped back to itself [Smith,P]
A function is just an arbitrary correspondence between collections [Shapiro]
A 'total' function must always produce an output for a given domain [Sider]
F(x) walked into a bar. The barman said.. [Sommers,W]